Transporation system for a sub-surface activity area

ABSTRACT

A transportation system comprising means for evacuating personnel from at least one area of activity ( 16 ) under a surface ( 13, 14 ), where the transportation system comprises at least one transport access passage ( 17 ) to the area of activity ( 16 ), at least one evacuation access passage ( 18, 28 ) to the area of activity ( 16 ) and in addition at least one transport conveyance ( 21 ) for evacuation through the evacuation access passage ( 18, 28 ).

The present invention relates to a transportation system for evacuating personnel from an area of activity under a surface, comprising an ordinary transport access passage in addition to a separate evacuation access passage with a transport conveyance which is dedicated to use in the event of an evacuation situation.

At present either floating or fixed installations are employed in connection with recovery of oil and gas at sea. Fixed installations comprise both platforms located on the seabed and pure seabed installations. One of the problems associated with recovery of oil on the Norwegian shelf on which there has been a great deal of focus is the risk of accidental spillage of oil, with associated pollution of the environment. This has been the dominant problem with regard to recovery plans in coastal areas, i.e. areas coinciding with or with a short drift time from areas of great environmental value or which are important for coastal-based fishing.

In the recovery of oil in northern waters, this problem becomes even more relevant on account of lower temperatures and greater risk of icing amongst other things, and the resultant restrictions with regard to collection of oil before it reaches land. At the same time the environment is more vulnerable. This places greater demands on safety margins, and thereby an increase in recovery costs. The result is a general skepticism to oil recovery in the northern waters since an accident leading to spillage, even though the chance of this happening is statistically very low, can entail such serious consequences for the environment. Similar evaluations also apply in some areas off the coast of Southern and Central Norway.

An alternative to conventional floating or fixed drilling rigs could be, for example, to locate drilling equipment in a cavern under the surface separated from the ocean or the sea, and use tunnels dug in under the ocean or the sea to the cavern where oil and gas can be recovered. Examples of such solutions are described in the American patent publications U.S. Pat. No. 2,331,072, U.S. Pat. No. 2,989,294, U.S. Pat. No. 3,486,571 and U.S. Pat. No. 4,463,987. In the last publication, U.S. Pat. No. 4,463,987, a system is described for subsea recovery of hydrocarbons where tunnels are dug down to an underground space where the recovery is carried out. In addition, the system comprises one or more spaces where hydrocarbons can be conveyed and temporarily stored in the event of an accident. There is also a tunnel in which personnel can escape in the event of accidents by walking or running. In this publication there is no indication of transport of personnel who have to be evacuated or any transportation system for such transport. Since this is not a theme of the publication, it has to be assumed that the intricate system of tunnels of which the invention consists relates to production of hydrocarbons from chambers located at a relatively short distance from the surface of the ground so that the personnel can get out by themselves.

In connection with road tunnels, from the three German patent applications DE 102 49 252 A1, DE 102 49 267 and DE 102 49 268 it is known to provide an escape route beside the roadway, thus enabling people to walk or run out if fire should break out in the tunnel. As in the case of the American publication above, the escape routes mentioned in these publications are intended for people on foot. There is no mention in the documents of the possibility of providing a separate evacuation system with stations for boarding special, dedicated transport conveyances located at the stations.

In the German patent application DE 21 27 156 a closed concrete bridge is disclosed which in some embodiments is designed with several levels for separating different kinds of traffic from one another, i.e. pedestrians, cars, lorries and trains have different passages in the bridge. This publication in no way relates to evacuation of a large number of people in the event of a serious accident, such as for example a blow-out from an oil or gas well.

By locating the actual recovery of oil/gas in cavities under the seabed with a supply tunnel from land, the present invention will be able to be utilised and possibly make it more acceptable to start operation of the field.

Where there is a wish to develop an oil/gas field by tunnelling through to a cavern in an area from which oil and/or gas are recovered in the conventional manner, it will be necessary to work out acceptable solutions with regard to safety and evacuation facilities for personnel in the event of an accident. An evacuation tunnel could be so long that it will not be practical for personnel working inside the tunnel to run or walk out of it. In the cases that are visualised, an operational area of this kind for recovery of oil/gas may be located at anything from a relatively short distance up to 60-70 km from a tunnel entrance.

Thus it is an object to provide a transportation system for use in production of oil/gas reservoirs from an underground cavity, which may be located under a body of water, where the safety of both personnel and environment are safeguarded.

It is a particular object of the present invention to provide a system for rapid and safe evacuation of personnel from an area of activity under a surface where there is a risk of accidents which will require a speedy evacuation of personnel from the said area of activity.

This is solved according to the invention as it is defined in the independent claim. Preferred embodiments of the invention are described in the following claims.

The present invention comprises an area of activity located under a surface, where activities are carried out that entail a risk of accidents which make it necessary to evacuate personnel working there. The activity taking place in the area of activity may be recovery of hydrocarbons, i.e. oil and/or gas. It is also possible to envisage that such areas of activity may include other activities such as, for example, more general mining operations or as a depot for explosive and/or inflammable materials or chemical substances and possibly also radioactive materials.

In most cases, the surface under which the area of activity lies will be a sea/ocean bed or a land surface, but it is also conceivable for the surface to be a water surface and that the area of activity is then located in an isolated position in the sea or is placed in an isolated position on the sea/ocean bed. Where the area of activity is located in the sea, a structure can be built round it to keep the surrounding water out, and similarly the area of activity can be covered by a structure if it is located on the sea/ocean bed.

The area of activity will have at least one transport access passage for transport of personnel, goods etc. to and from the area of activity during ordinary operation. The transport access passage may be an ordinary tunnel extending from a point on shore, i.e. on an island or on the mainland through solid rock/soil to the area of activity. The whole or parts of the transport access passage may also be envisaged in the form of a sunken tunnel or a floating tunnel passing through the water. If several separate accesses are made to the area of activity, the different accesses may be designed in different ways, for example a first access may be in the form of an ordinary tunnel through solid rock, while a second access may be designed with the whole or parts of the access as a sunken tunnel.

For evacuating personnel in connection with an accident in the area of activity, according to the invention the transportation system comprises at least one separate evacuation access passage. In order to ensure that an escape route is always ready for immediate evacuation, the evacuation access passage is dedicated to this purpose, and is therefore not meant to be used for transport in connection with ordinary operation in the area of activity.

The evacuation access passage and the transport access passage will normally be placed in the same bore in a common tunnel, but it is also conceivable for the evacuation access passage and the transport access passage, wholly or partly, to follow different passages to the area of activity.

According to the invention, the transportation system also comprises at least one unit of a dedicated transport conveyance which is stationed in the evacuation access passage for evacuation of personnel. This transport conveyance will preferably be a vehicle on rails, but may also be a vehicle which does not run on rails.

In connection with the area of activity, the invention further comprises at least one boarding station for boarding the transport conveyance which is dedicated to use during evacuation. During normal operation, at least one unit of this transport conveyance will always be stationed at the boarding station(s) ready for use in the event of an accident. The boarding station(s) is separated from the area of activity by means of a structure designed to withstand fire and explosions, which may be expected to occur in the event of an accident in the area of activity, for long enough to enable all personnel to be evacuated from the area. It is also possible to place the boarding station(s) in a separate area relatively close to, but separated from the area of activity by solid rock/soil with a thickness which is sufficient to withstand the stress of fire and explosions in the event of an accident, at least for long enough to enable all personnel to be evacuated. It is also possible to place the boarding station(s) in a separate area separated from the area of activity by solid rock as mentioned above combined with a fire and explosion-proof structure.

In order to reduce the chance of any dangerous gases infiltrating the evacuation access passage and the boarding stations in the event of an accident, the air pressure in the boarding station(s) and possibly in the evacuation access passage may be made at least as great as and preferably slightly greater than the ambient pressure in the area of activity and the transport access passage. Inside the transport conveyance the pressure will be at least as great as in the boarding station, and in order to further increase the protection against infiltration of undesirable gases, it may be higher than the pressure in the boarding station. In addition, each boarding station has at least one access from the area of activity or the transport access passage which is fluid-tight when it is closed.

Where the transport access passage and the evacuation access passage are provided in the same bore, they are separated by a solid structure which can withstand fire and explosions, particularly near the area of activity where the chance of serious accidents is greatest, but also through the whole transport and evacuation access passage if the products produced in the area of activity are inflammable and explosive and are sent out through the transport access passage. If hydrocarbons are involved, they will be able to be transported through one or more pipelines or by means of tankers, and possibly by means of both pipeline(s) and tankers. The evacuation access passage and the transport access passage may be envisaged located side by side in the bore or one above the other, preferably with the evacuation access passage located below the transport access passage. At all events the evacuation access passage and the transport access passage must be separated by a solid structure as mentioned above.

The transport tunnel may advantageously be further provided with at least one means for closing off the transport tunnel completely in connection with an accident. The means may, for example, be in the form of a door that is rolled or pushed in from the side, down from the roof or up from the floor. What is important is that this door is solid and can withstand fire and powerful explosions. In order to check and/or prevent the spread of fire and undesirable gases in the transport tunnel, it is advantageous to place such means at regular intervals throughout the transport tunnel which closes off the part of the transport tunnel where fire and/or undesirable gases are detected by means of sensors. Between two such closing-off means, the transport tunnel may comprise a fluid-tight access, either directly to the evacuation access passage, or to a boarding station for the evacuation access passage. This or these boarding station(s) may be of the same type as that described above and may also possibly comprise a stationed transport conveyance.

The present invention will now be described by means of a preferred, but not limiting embodiment, where reference is made to the attached drawings, in which:

FIG. 1 illustrates a map of an area where the use of the present invention may be envisaged.

FIG. 2 illustrates a section of a stretch of open sea and the substructure under the sea associated with a geographical area where the invention may be used.

FIG. 3 illustrates an area of activity with transport access passage and evacuation access passage viewed from the side.

FIG. 4 illustrates a section through a tunnel with the transport access passage located above the evacuation access passage in a common bore.

FIG. 5 illustrates a section through a tunnel with the transport access passage located beside the evacuation access passage in a common bore.

FIG. 6 illustrates a boarding station with an access and a transport conveyance for evacuation.

FIG. 7 illustrates an area of activity with transport access passage and evacuation access passage viewed from above.

FIG. 8 illustrates boarding stations in connection with the evacuation access passage outside the area of activity.

In FIG. 1 a map is illustrated of an area where the use of the present invention may be envisaged. A point 10, illustrated here located on an island, but which naturally may be located on the mainland, may comprise a plant for refining oil/gas. An oilfield is also illustrated located approximately 60 km out at sea.

In FIG. 2 a section of the subsurface is illustrated from an area also shown in FIG. 1, where a tunnel 15 is indicated running under the seabed 14 from a terminal 12 to an area of activity 16 located in or near an area where there is a deposit of oil/gas. The terminal 12 may be a single access to the tunnel 15, but may also comprise a plant for further refining of the oil/gas produced in and transported from the area of activity 16.

FIG. 3 is a schematic view of how the design of an area of activity may be envisaged. The tunnel 15 from the terminal 12 may comprise one or more branches in the area where drilling for oil and/or gas is to take place. At the end of a branch, the tunnel 15 may be envisaged extended to an area of activity 16 which is made large enough to provide space for necessary production equipment. A drilling rig 19 is depicted in the figure, but there may well be more than one drilling rig in each area of activity. In the figure it is also shown that the tunnel 15 is divided into a transport access passage 17 and an evacuation access passage 18. During normal operation, transport of personnel, equipment etc. will be conducted through the transport access passage 17, while the evacuation access passage 18 will only be used in situations where an evacuation of personnel is imperative.

Two embodiments of the tunnel 15 are illustrated in FIGS. 4 and 5. In FIG. 4 we can see that the tunnel 15 is divided horizontally, with the transport access passage 17 located above the evacuation access passage 18. The transport access passage comprises roadways 25 for vehicles such as cars, trucks and articulated lorries. Beside the roadways 25, pipelines 26 may be envisaged for transport of oil and/or gas from the area of activity 16. These pipelines may well be separated from the transport access passage 17 by a non-illustrated partition device. Just beneath the roof of the tunnel 15, ducts/pipes 27 may be placed for cables and the like or transport of necessary fluids to/from the area of activity 16. Oil/gas pipelines 26 and ducts/pipes 27 may, of course be located as appropriate in other positions in the transport access passage 17. The evacuation access passage 18 is located under the roadway 25 in the transport access passage 17. The two passages are physically separated by a solid partition structure 24 which is designed to be able to withstand fire and explosions in the event of an accident for long enough to give personnel located in the area of activity 16 and/or the transport access passage 17 a reasonable chance of getting out through the evacuation access passage 18. For example, the partition structure 24 may be designed in such a manner that it can withstand temperatures that can be expected during a fire for one hour, or possibly for a longer or shorter period, before it collapses. In the same way it may be designed in such a manner that it can withstand explosions of maximum anticipated strength in the event of an accident.

In FIG. 5 a second embodiment is illustrated where the transport access passage 17 and the evacuation access passage 18 are located side by side, physically separated by a solid partition structure 24 which is designed to be able to resist fire and explosions in the event of an accident in the same way as described above. From the figure it can be seen that the pipelines 26 for transport of oil/gas are located above the evacuation access passage 18 and ducts/pipes 27 are placed directly under the roof of the tunnel, but the location of the pipeline 26 and the ducts 27 may of course be implemented in a different way if so desired. The partition structure 24 is designed in the same way as explained above, i.e. it must be designed with a view to being able to withstand fire and explosions of anticipated strength for long enough to give personnel working in the area of activity and/or stationed in the tunnel enough time to get out by means of the evacuation access passage 18.

The evacuation access passage 18 has at least one boarding station 20 located in or near the area of activity 16. FIG. 6 illustrates an embodiment of a boarding station located at the end of an evacuation access passage 18. At the end of the evacuation access passage at least one unit of a transport conveyance 21 is stationed ready for immediate evacuation if necessary. In the figure a transport conveyance on rails 21 is shown, but the transport conveyance may also comprise a vehicle that does not run on rails. The boarding station is separated from the area of activity by a partition structure 24 which is designed to withstand fire and explosions of maximum anticipated strength for long enough to give personnel a reasonable chance of being evacuated through the evacuation access passage 18. The evacuation access passage 18 may be provided in a separate tunnel bore at the area of activity 16. In this case the partition structure 24 consists of bedrock, selected in a thickness that can withstand fire and explosions as indicated above. The partition structure 24 may also be constructed inside the area of activity 16, preferably along the edge as indicated in FIG. 7, in which case it may consist of, for example, reinforced concrete. The partition structure 24 may also be envisaged consisting of a combination of bedrock and a structure composed of, for example, reinforced concrete. Other constructional materials such as steel will also be possible and it will be up to a skilled person to select the most suitable material or materials. The boarding station 20 also comprises an access 22 from the area of activity 16. This access is kept automatically closed by a mechanism which, for example, may comprise a spring mechanism. The access 22 also comprises means to ensure that it is fluid-tight in a closed state. Inside the boarding station 20, and possibly the evacuation access passage 18, the air pressure is slightly higher than the ambient pressure in the area of activity 16 in order as far as possible to prevent gases that may develop in the event of fire or explosion from infiltrating the boarding station and/or the evacuation access passage. The boarding station also comprises an access 23 for the transport conveyance 21 which is dedicated to evacuation of personnel. The air pressure in the transport conveyance 21 should be at least as great as the pressure in the boarding station 20, but may well be higher, thereby providing extra protection against infiltration of undesirable gases into the transport conveyance 21 in the event of an accident.

In FIG. 7 an area of activity 16 is illustrated comprising an evacuation access passage 18 divided into two branches 28 at the entrance to the area of activity 16, with the result that in connection with this area of activity there are two boarding stations 20 for access to the transport conveyance 21 in a branch 28 of the evacuation access passage 18. The evacuation access passage may comprise as many branches 28 as are considered necessary for a given area of activity 16. Each branch 28 will normally comprise one boarding station 20 with an associated transport conveyance 21 in order to avoid “traffic problems” in the event of evacuation. Where two branches 28 meet in a branch intersection 29, the traffic of transport conveyances 21 may be controlled by means of, for example, traffic lights that are controlled automatically by a system of sensors which detect arriving transport conveyances 21. If the transport conveyance 21 is driverless, it may advantageously be guided automatically through the branch intersection 29 as explained below.

The evacuation access passage 18 may also comprise one or more boarding stations 20 between the area of activity 16 and the terminal 12. In FIG. 8 an example is illustrated where the evacuation access passage 18 comprises two branches 28 where each of the branches has a boarding station 20. The boarding stations may advantageously be designed in the same way in or beside an area of activity 16 as described above. At each boarding station 20 a dedicated transport conveyance 21 is standing ready for use in case an accident happens. The number of boarding stations in the tunnel 15 may be anything from zero to as many as are considered necessary in order to evacuate all the personnel in a secure manner.

The transport conveyance 21 may be designed in such a manner that it is fluid-tight against the environment when the access 23 to the transport conveyance is closed, thereby preventing any undesired gas that has leaked into the evacuation tunnel from infiltrating the transport conveyance 21. Furthermore, the transport conveyance 21 may advantageously be driverless. In this case the transport conveyance will be provided with means for starting it. This means may naturally be used for starting the transport conveyance on several occasions during the journey through the evacuation tunnel if this should be necessary. The transport conveyance 21 also comprises an automatic control system which is capable of guiding several transport conveyances 21 through the branch intersections 29, for example, according to a system where the transport conveyances are let through a branch intersection in the order of their arrival. Transport conveyances from one or more branches 28 may be given priority in a desired order. The transport conveyances 21 also include brakes which are controlled automatically by the same control system. The system receives signals from sensors at the branch intersections together with one or more sensors which record whether another transport conveyance 21 or other objects are located in front on the railway or roadway in the evacuation tunnel. On the basis of the data received from the sensors, any braking of the transport conveyance 21 that is required can be calculated and implemented. The transport conveyance 21 may of course also be arranged so that it is operated manually by a person. As explained above, the branch intersections 29 can then be provided with traffic lights which detect arriving units of the transport conveyance 21 and give them the green light, possibly in order of priority. 

1. A transportation system for an underground area of activity comprising an evacuation access passage extending in a tunnel from the area of activity to an entrance at the surface of the ground, and at least one boarding station in the immediate vicinity of the area of activity, the boarding station being separated from the area of activity by a partition structure to which boarding station the evacuation access passage extends, and at least one dedicated transport conveyance which is stationed at the at least one boarding station for evacuation through the evacuation access passage.
 2. (canceled)
 3. A transportation system according to claim 1, wherein the partition structure comprises solid rock or soil, a structure or a combination of the two, and where the partition structure forms a fire and explosion-proof partition between the boarding station and the area of activity.
 4. A transportation system according to claim 1, wherein at least one boarding station is located in the immediate vicinity of the tunnel.
 5. A transportation system according to claim 3, wherein the boarding station is separated from the tunnel by a partition structure.
 6. A transportation system according to claim 4, wherein the partition structure comprises solid rock, a structure or a combination of the two, and where the partition structure forms a fire and explosion-proof partition between the boarding station and the tunnel.
 7. A transportation system according to claim 1, wherein the boarding station comprises an access which is fluid-tight in a closed state.
 8. A transportation system according to claim 1, wherein inside the boarding station, and possibly in the evacuation access passage, there is an overpressure relative to the ambient pressure in the area of activity and the evacuation access passage and that the air pressure inside the transport conveyance is at least as great as the pressure in the boarding station.
 9. A transportation system according to claim 7, wherein the pressure inside the transport conveyance is higher than the pressure in the boarding station.
 10. A transportation system according to claim 1, wherein the transport conveyance comprises a vehicle on rails.
 11. A transportation system according to claim 1, wherein the transportation system comprises a separate transport access passage and that the transport access passage and the evacuation access passage are provided in separate tunnels.
 12. A transportation system according to claim 1, wherein the transportation system comprises a separate transport access passage and that the transport access passage and the evacuation access passage are provided in the same tunnel.
 13. A transportation system according to claim 11, wherein the evacuation access passage is separated from the transport access passage by a fire and explosion-proof structure. 